Transfer pump



Pril 29 1969 LAGONEGRO TRANSFER PUMP Filed Aug. 29, 1967 NTOR. a g

ATTO EY United States Patent 3,440,966 TRANSFER PUMP Paul R. Lagonegro, Henrietta, N.Y., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Aug. 29, 1967, Ser. No. 664,203 Int. Cl. F04b 49/00, 43/08; F04d /00 U.S. Cl. 103-37 3 Claims ABSTRACT OF THE DISCLOSURE In a preferred form, this disclosure relates to a rotary fluid pump utilizing a pair of symmetrically spaced "balls purging a crescent-shaped chamber when rotated to build a fluid pressure from one end of the cerscent-shaped chamber to the other.

This invention relates to fluid pumping apparatus and more particularly to a transfer pump driven by an electric motor that rotates a pair of balls in sequence through a chamber purging fluid therefrom developing a pressure of the fluid at the outlet which is positioned at an extreme in the crescent shaped depression from the position of the inlet.

The prior art shows many types of transfer pumps but the type disclosed herein is an improvement thereover in that a positive displacement pump is shown which develops a fluid pressure of a predetermined magnitude but ceases to be a displacement pump in the strict sense of the term when viscosity of the fluid changes or the speed of motor rotation causes an excessive pressure to be developed at an outlet. When this situation occurs, the balls, which normally purge a pumping chamber by rolling a diaphragm through the chamber, will be driven back against a spring loaded clutching device to bring about a certain decrease in pump output. Therefore, the pump disclosed herein automatically adjusts for output pressures in excess of a desired pressure.

It is an object of the present invention to provide an improved fluid pump which automatically adjusts for an overpressure condition.

It is another object of the present invention to provide an improved fluid pump utilizing a pair of balls acting against a resilient diaphragm normally enclosing a pumping chamber to purge such chamber of fluid thereby building up a pressure in the fluid.

It is still another object of the present invention to provide a fluid pump in keeping with the aforementioned objects which is very simple in structure while utilizing very little space at the output end of a drive motor.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a sectional view of the subject invention;

FIGURE 2 is a partial sectional view with parts broken away taken along the line 2-2 of FIGURE 1;

FIGURE 3 is a partial sectional view similar to FIG- URE 1 but with the drive shaft rotated 90 degrees.

Referring to FIGURE 1, an electric motor, generally designated by the numeral 10, has an output shaft 12. It is understood that the type of electric motor 10 is not critical but the speed of rotation of said motor must be matched to the pump output so that the desired pressure in a given range allows the most desirable positive displacement action of the pump in that selected pressure range.

Pump housing 14 includes a rearwardly extending sub- Patented Apr. 29, 1969 stantially cylindrical shaped member arranged to engage the outer periphery of electric motor 10. It is only necessary that housing .14 be mounted so that it is non-rotatable with respect to motor 10 because any axial movement of the housing 14 relative to the motor 10 is prevented by the mode of attachment to drive shaft 12 to be hereinafter described.

A crescent shaped groove 16 is formed in housing 14 and is more clearly seen in FIGURE 2. Groove 16 has an inlet 18 and an outlet 20 for the ingress and egress of fluid, assuming the output shaft 12 is rotated in a clockwise manner as viewed in FIGURE 2.

Referring to FIGURE 1, diaphragm 22 is fitted against an end face of housing 14 so that the crescent-shaped groove 16 is completely enclosed on its open side by a diaphragm. This forms a pumping chamber 24 which is more clearly seen in FIGURE 3. An auxiliary housing plate 26 is attached to housing 14 in any well-known manner,trapping diaphragm 22 therebetween, to completely seal the crescent-shaped groove 16 from the exterior of the pump. A constant curved groove complementary to the mean chord diameter of crescent-shaped groove 16 is formed in housing plate 26 so that the base of the crescent-shaped groove .16 and the base of groove 28 are on the same plane. Balls 30 fit into grooves 16 and 28 substantially conforming to the contour of the groove but with suflicient clearance therebetween to allow diaphragm 22 to be deformed at the base thereof.

Referring to FIGURE 1, ball race place 32 is carried in a fixed manner with respect to output shaft 12 and includes peripheral depressions 34 substantially the same shape as a semicircle having a radius slightly greater than the radius of the balls 30. Therefore, it is seen that a rotation of plate 32 will drive balls 30 in grooves 28 and 16 in a rotational manner with respect to shaft 12.

A holding plate 36 is slidable on output shaft 12 and is held against balls 30 by a force placed on spring 38 by adjustable nut 40. The amount of force generated against holding plate 36 by nut 40 determines the positive displacement capability of the pump and can be varied in a given installation within certain parameters to vary the amount of pump output.

In operation, the electric motor 10, when energized, rotates output shaft 12 in a clockwise direction, for example, as viewed in FIGURE 2. Referring to FIGURE 2, one of the balls 30 moves from inlet 18 in crescent-shaped groove 16 deforming diaphragm 22 into the base of chamber 24 in front of it. It is obvious that, when the ball enters crescent-shaped groove 16, the groove 16 goes from a zero dimension near inlet 18 to a maximum cross-sectional dimension, as seen in FIGURE 3. The fluid present in chamber 24 is forced in front of the advancing ball and diaphragm to outlet 20. Due to the diminishing of the cross-sectional dimension of groove 16 approaching outlet 20, a pressure buildup in groove 16 occurs at outlet 20. It should also be noted that as ball 30 depressing diaphragm 22 moves through groove 16, diaphragm 22 rebounds behind ball 30, resulting in a slightly negative pressure buildup drawing more fluid through inlet 18 refilling chamber 24. As rotation of output shaft 12 continues, the next ball moves past inlet 18 to repeat the process. Therefore, for each revolution of shaft 12 two pressure surges are felt at outlet 20. An even pressure pulse is set up at outlet 20 having a sinusoidal characteristic. Depending on the speed of rotation of shaft 12, pressure pulses canbe regulated as to frequency so that a practically even pressure buildup is experienced at outlet 20 relative to inlet 18.

The subject mechanism is particularly adapted for use in an application such as a windshield washer pump. However, it is obvious that the pump disclosed herein is not limited to that application but finds utility pumping any fluid where a relatively constant pressure is desirable. As previously stated, the amount of force exerted by spring 38 on plate 36 is determined by nut 40. In this manner, balls 30 are kept against diaphragm 22 and, if an overpressure condition is experienced, holding plate 36 can be deflected slightly on output shaft 12 lifting ball 30 and diaphragm 22 slightly, resulting in a relieving of the pressure to a desired level.

Although the illustrated embodiment of the present invention has been described in great detail, it should be apparent that certain modifications, changes, and adaptations may be made therein without departing from the spirit of the present invention.

What is claimed is:

1. A fluid pump comprising: a main pump housing member having an aperture therethrough through which a drive shift is adapted to extend, said pump housing member having an end face, a crescent shaped groove formed in said end face, said groove being in communication with a fluid inlet opening at one end thereof and a fluid outlet opening at the other end thereof, a resilient diaphragm covering said end face and forming with said groove a pumping chamber, a plurality of spaced spherical balls rollable on said diaphragm in response to rotation of said drive shaft for progressively deforming said diaphragm into said groove to purge fluid in said pumping chamber from said inlet opening toward said outlet opening and thereby increase the pressure of the fluid, means carried by said drive shaft for rotating said balls on said diaphragm in a circular path and for maintaining the balls spaced from each other, auxiliary housing means overlying and clamping the diaphragm against said end face except for the area at the crescent shaped groove, said auxiliary housing means also defining an arcuately extending groove of semi-circular cross-sectional shape and with the bottommost points of said arcuately extending groove and said crescent shaped groove in the main housing member lying in a common plane extending radially of the drive shaft, said crescent shaped groove and said arcuately extending groove together forming an annular groove for said balls to travel in, means for connecting said auxiliary housing means to said main pump housing and for holding the diaphragm against said end face, and yieldable force applying means engageable with said balls for biasing the same into engagement with said diaphragm.

2. In combination, a drive motor having a housing and an output shaft, and a fluid pump, said fluid pump comprising: a generally cup shaped main pump housing having bottom and side wall portions which define a chamber for receiving said motor housing, said bottom portion having an aperture therethrough through which the output shaft of the motor extends, said bottom portion on its face remote from said motor housing having a crescent shaped groove formed therein, said groove being in communication with a fluid inlet opening at one end thereof and a fluid outlet opening at the other end thereof, a resilient diaphragm covering said face of said bottom portion and forming with said groove a pumping chamber, a plurality of spaced spherical balls rollable on said diaphragm in response to rotation of said drive motor for progressively deforming said diaphragm into said groove to purge fluid in said pumping chamber from said inlet opening toward said outlet opening and thereby increase the pressure of the fluid, means carried by said output shaft for rotating said balls on said diaphragm in a circular path and for maintaining the balls spaced from each other, auxiliary housing means overlying and clamping the diaphragm against said end face of said bottom portion except for the area at the crescent shaped groove, said auxiliary housing means also defining an arcuately extending groove of semi-circular cross-sectional shape and with the bottommost points of said arcuately extending groove and said crescent shaped groove lying in a common plane extending radially of the output shaft of said drive motor, said crescent shaped groove and said arcuately extending groove together forming an annular groove for said balls to travel in, means for connecting said auxiliary housing means to said cup shaped pump housing and for holding the diaphragm against said end face of said bottom portion, and yieldable force applying means engageable with said balls for biasing the same into engagement with said diaphragm.

3. The combination as defined in claim 2 wherein said yieldable force applying means comprises a plate slidably carried by said output shaft and engageable with said balls, a member carried by said output shaft, and a compression spring having one end in abutting engagement with said plate and the other end in abuttng engagement with said member, said member being threadably engaged with said output shaft and adjustably positionable axially of the output shaft to vary the biasing force of the spring.

References Cited UNITED STATES PATENTS 2,752,852 7/1956 Olfutt 103149 X 2,841,091 7/1958 Schaurte 103-149 2,897,767 8/1959 Cordis l03149 2,915,983 12/1959 Berrian 103149 2,920,578 1/1960 Schaurte 103-149 2,402,244 6/1946 Elberty 103-38 WILLIAM L. FREEH, Primary Examiner.

US. Cl. X.R. 103-149 

